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Used Antibiotics (used + antibiotics)
Selected AbstractsThe model of fungal population dynamics affected by nystatinINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 1 2010Sergei I. Voychuk Abstract Fungal diseases are acute problems of the up-to-day medicine. Significant increase of resistance of microorganisms to the medically used antibiotics and a lack of new effective drugs follows in a growth of dosage of existing chemicals to solve the problem. Quite often such approach results in side effects on humans. Detailed study of fungi-antibiotic dynamics can identify new mechanisms and bring new ideas to overcome the microbial resistance with a lower dosage of antibiotics. In this study, the dynamics of the microbial population under antibiotic treatment was investigated. The effects of nystatin on the population of Saccharomyces cerevisiae yeasts were used as a model system. Nystatin effects were investigated both in liquid and solid media by viability tests. Dependence of nystatin action on osmotic gradient was evaluated in NaCl solutions. Influences of glucose and yeast extract were additionally analyzed. A "stepwise" pattern of the cell death caused by nystatin was the most intriguing. This pattern manifested in periodical changes of the stages of cell death against stages of resistance to the antibiotic. The mathematical model was proposed to describe cell-antibiotic interactions and nystatin viability effects in the liquid medium. The model implies that antibiotic ability to cause a cells death is significantly affected by the intracellular compounds, which came out of cells after their osmotic barriers were damaged © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Antimicrobial profiles of periodontal pathogens isolated from periodontitis patients in the Netherlands and SpainJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2005A. J. Van Winkelhoff Abstract Background and Aim: Antimicrobial resistance of periodontal pathogens towards currently used antibiotics in periodontics has been investigated in a previous study. Microbial resistance in the periodontal microflora was more frequently observed in Spanish patients in comparison with Dutch patients. The aim of the present study was to compare antimicrobial susceptibility profiles of five periodontal bacteria isolated from periodontitis patients in Spain and in the Netherlands. Material and Methods: Subgingival plaque samples from adult patients with periodontitis were collected and cultured on selective and non-selective plates. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Micromonas micros were isolated and used for minimal inhibitory concentration tests using the Epsilometer (E-test) technique. Eight different antibiotics were tested on all bacterial isolates. MIC50 and MIC90 values for each antibiotic and each species were determined and the percentage of resistant strains was calculated. Results: Significantly higher MIC values were noted in Spanish strains of F. nucleatum for penicillin, ciprofloxacin, of P. intermedia for penicillin, amoxicillin and tetracycline, of M. micros for tetracycline, amoxicillin and azithromycin, and of P. gingivalis for tetracycline and ciprofloxacin. Based on breakpoint concentrations, a higher number of resistant strains in Spain were found in F. nucleatum for penicillin, amoxicillin and metronidazole, in Prevotella intermedia for tetracycline and amoxicillin, and in A. actinomycetemcomitans for amoxicillin and azithromycin. Resistance of P. gingivalis strains was not observed for any of the antibiotics tested both in Spain and the Netherlands. Conclusions: Differences exist in the susceptibility profiles of periodontal pathogens isolated from periodontitis patients in Spain and in the Netherlands. This implicates that antibiotic susceptibility testing is necessary to determine efficacy of antimicrobial agents. Also, clinical studies with antibiotics should take these differences into account. The information from the present study indicates that it may not be possible to develop uniform protocols for usage of antibiotics in the treatment of severe periodontitis in the European Union. [source] Surface-enhanced resonance Raman spectroscopy of rifamycins on silver nanoparticles: insight into their adsorption mechanismsJOURNAL OF RAMAN SPECTROSCOPY, Issue 9 2006Barry D. Howes Abstract Three widely used antibiotics from the rifamycin family, rifamycin SV sodium salt, rifampicin and rifaximin, have been characterized by resonance Raman (RR) and surface-enhanced resonance Raman spectroscopy (SERRS). SERRS spectra were recorded using aqueous silver colloidal dispersions prepared with two reducing agents, sodium borohydride and hydroxylamine hydrochloride, for a range of pH values to identify the SERRS-active substrate surface most suitable for each of the three antibiotics. Rifampicin was found to give intense SERRS signals only for the borohydride-reduced colloid and only at pH < 7.7, whereas the hydroxylamine HCl-reduced colloid was the best substrate for rifaximin, giving considerably more intense SERRS spectra than the borohydride colloid. SERRS spectra of rifaximin were observed only at pH < 7.0. It is proposed that the marked pH dependence of the SERRS enhancement results from a transition from an anionic to a neutral zwitterionic state. SERRS spectra of rifamycin SV were not observed for any experimental conditions. The antibiotics display remarkably contrasting SERRS behaviour, reflecting differences in the nature of the substituent groups on the chromophore ring. A vibrational assignment of the RR spectra and detailed comparison between the RR and SERRS data have given insight into the mechanism of adsorption of the antibiotics onto the Ag surface. Rifampicin and rifaximin adsorb adopting an approximately similar vertical orientation of the chromophore ring with respect to the surface; however, rifampicin adsorbs by direct chemical interaction with the Ag whereas rifaximin does not form a direct bond with the Ag surface. Copyright © 2006 John Wiley & Sons, Ltd. [source] Superficial community-acquired skin infections: prevalence of bacteria and antibiotic susceptibility in FranceJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 12 2009G Lorette Abstract Objective, Evaluation of the susceptibility to currently used antibiotics of bacteria, particularly S. aureus isolated from superficial community- acquired skin infection and to compare results with those from an earlier study. Methods, Every dermatologist in community practice participating in the study was asked to include the first two patients consulting them for superficial cutaneous bacterial infection. Swab specimens collected from the skin infection were sent to a central laboratory. Results, The dermatologist enrolled 390 patients in the study. The rate of positive culture was 49%, 259 bacterial strains were isolated. S. aureus was the major species (56.8% of all isolated strains). S. aureus was resistant to methicillin in 4%. All strains of S. aureus were susceptible to pristinamycin and mupirocin. Conclusions, The results of the two epidemiological studies of superficial community acquired skin infections with a comparable methodology at a 6-year interval demonstrated that the prevalence of CA-MRSA skin infection remained low in this setting. [source] A guide to antibiotic resistance in bacterial skin infectionsJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2005G Perera ABSTRACT The emergence of bacterial resistance to commonly used antibiotics is not new. In this review we have tried to cover the ever increasing problems facing the treatment and containment of bacterial skin infections. We have tried to give an overview of the varied mechanisms by which bacteria gain and spread antimicrobial resistance, whilst dealing with the patterns of resistance exhibited by some of the commonly encountered organisms. Where there is evidence, we have formulated an approach on how to tackle antibiotic resistance. Where there is a lack of evidence we have formulated what we perceive to be appropriate guidelines. [source] How pediatricians manage asthma in ThailandPEDIATRIC PULMONOLOGY, Issue 2 2001Pakit Vichyanond MD Abstract Currently, there is no existing information regarding prescribing practices for the management of childhood asthma among pediatricians in Thailand. In order to evaluate the management standards for childhood asthma in Thailand, 400 self-administered questionnaires were randomly mailed to nonacademic pediatricians throughout Thailand, asking questions about their preferences in the treatment of childhood asthma. One hundred and seventy-four of these 400 questionnaires were returned (a response rate of 43.5%). Data were analyzed using the descriptive module of the Epi-info 6 program. For acute asthma, 17% of the respondents used objective measures such as peak flow meters in assessing asthma severity and severity of acute asthma attacks. The drug of first choice for treating acute attacks was a nebulized beta-agonist q 20 min (81.8%). Although 93% indicated that they had used theophylline for treating acute attacks, most would reserve the drug for patients with severe symptoms. Corticosteroids were reserved for those with severe attacks (91.7% both for clinic and for in-hospital settings). Hydrocortisone was the most preferred corticosteroid preparation (59.8%). Ninety-seven percent used antibiotics in treating acute asthma, but only with appropriate indications. For chronic asthma, a strong preference was observed for oral beta-agonists as the bronchodilator of choice (88%). For moderately severe asthmatics, theophylline was still preferred by 41% of the responders. Among prophylactic agents, ketotifen was the most favored drug (90.4%), whereas inhaled steroids and cromolyn were chosen by 9.6% and 2.4%, respectively. Eighty-five percent indicated that they would prescribe prophylactic agents for 1 year or less. Forty-two percent never considered allergy evaluation as a part of a workup for childhood asthma. Certain prescribing practices of childhood asthma management in Thailand were observed among pediatricians, i.e., 1) low frequency of using objective measures in assessing asthma severity among pediatricians; 2) frequent use of theophylline and antibiotics in the treatment of acute asthma; 3) late introduction of corticosteroids in treating acute asthma; 4) preference for oral bronchodilators; and 5) preference of ketotifen as the prophylactic drug of choice. This survey provides baseline data and will aid in the evaluation of management guidelines for childhood asthma in Thailand. Pediatr Pulmonol. 2001; 32:109,114. © 2001 Wiley-Liss, Inc. [source] Risk of drug-related problems for various antibiotics in hospital: assessment by use of a novel method,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 8 2008Hege Salvesen Blix MSc Abstract Purpose To investigate the use of antibiotics in hospitals, to explore drug-related problems (DRPs) linked to antibiotics and to introduce a novel way of expressing the risks accompanying use of various antibiotics. Methods Patients from internal medicine departments in four Norwegian hospitals were prospectively included in 2002. Demographics, drugs used, medical history, laboratory data and clinical/pharmacological risk factors were recorded. DRPs were identified by clinical pharmacists and assessed in multidisciplinary hospital teams. A new term, the drug risk ratio, was established and defined as the number of times the antibiotic was associated with DRPs in relation to the number of times it was used. Results Out of the 668 patients included, 283 patients (42%) used antibiotics (AB users). AB users were older (76.2 vs. 73.9), used more drugs on admission (5.1 vs. 4.4) and had more DRPs (3.0 vs. 2.2) than non-users. The DRP categories no further need for drug, non-optimal drug and non-optimal dose were most frequently observed. The drug risk ratio, calculated for 12 antibiotic groups, was highest for aminoglycosides (0.77), , -lactamase-resistant penicillins (0.56), macrolides (0.54) and quinolones (0.48) and lowest for first- and third-generation cephalosporins, 0.17 and 0.13, respectively. Conclusions Nearly half of the hospitalised patients were prescribed antibiotics and antibiotic associated DRPs occurred frequently. The drug risk ratio for the different antibiotic groups varied with a factor of six from the lowest to the highest. A high drug risk ratio would alert of antibiotics which require heightened awareness when going to be used in clinical practice. Copyright © 2008 John Wiley & Sons, Ltd. [source] High-performance liquid chromatographic method for simple and rapid determination of linezolid in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 8 2006Lauren M. Boak Abstract A simple high-performance liquid chromatographic (HPLC) method was developed and validated for rapid quantification of linezolid in human plasma. Protein precipitation using a mixture of 5% trichloroacetic acid and methanol (3:1, v/v) provided a straightforward method of sample preparation and the internal standard eperezolid was employed. A concentration range from 0.20 to 40.0 mg/L was utilized to construct calibration curves, and analysis of low- (0.40 mg/L), medium- (7.50 mg/L) and high-quality (25.0 mg/L) control samples revealed excellent reproducibility (,3.88%) and accuracy (,4.20%). The recovery of both linezolid and eperezolid was approximately 100%. No interference was observed at the retention times of linezolid and eperezolid from blank plasma or eight commonly used antibiotics. Tests confirmed the stability of linezolid in plasma during three freeze,thaw cycles, on the bench during 24 h and during long-term storage of frozen plasma for up to 12 weeks; in extracts it was stable in the HPLC autosampler over 12 h. Overall, this assay offers a highly simplistic approach to quantifying linezolid in plasma, and would be well suited to clinical pharmacokinetic, pharmacodynamic and toxicodynamic analyses. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||